Recycling, for both environmental and economic purposes has become quite common. This is particularly the case where the material is not normally considered biodegradable, as with plastics, that is synthetic resinous materials.
In order to successfully recycle plastics, particularly plastic containers, contaminants must be kept at a minimum. This is necessary for a variety of reasons including protection of the recycling equipment and maintaining the integrity of the recycled material. To this end, it is not uncommon for limits to be established for acceptable amounts of retained contents, above which plastic containers are not considered recyclable.
This is a particular problem with conventional caulk cartridges, normally made of an appropriate rigid plastic material, for example polyethylene, in that such cartridges do not completely empty during normal usage, leaving an unacceptable residue of paste-like material, whether this be caulk, sealing compounds, adhesive, or the like.
Cartridge designs have been developed which attempt to deal with this problem of excess retained contents. Most such designs involve projections on the internal plunger which attempt to expel the last remaining volume of contents by entering into the nozzle.
Cartridges of European design do not normally include an integral nozzle as is standard in American design cartridges. Utilizing a separate releasable nozzle, a design has been developed which incorporates an interior tube extending into the cartridge. When dispensing is complete the nozzle may be removed, capturing sufficient remaining content within the interior tube to allow the separated cartridge body to be considered recyclable. However, such an arrangement cannot be applied to the standard domestic design wherein the nozzle is an integral part of the cartridge or cartridge end panel. It is also unlikely that users of the cartridges will be willing to take the time to unscrew or otherwise manually grasp and manipulate the nozzle in order to separate the recyclable portion of the cartridge.